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NOTE: This guide has been updated to include all the information on the both the Normal and Heroic versions on the bosses.

Time to enter the Stonecore

The Stonecore instance is located in Deepholm, the earth elemental plane. The instance portal is located right in the center of the zone on a platform up the side of the pillar where you enter the zone, on the southeast side. Once you know its rough location it is extremely easy to find. This instance is meant for players level 82-84 and can be extremely challenging if you are on the low end of that scale.

Being based in an earth elemental zone it should be no surprise to players that the instance has a very rough rock hewn appearance. It looks like a cave carved out of a mountain, while still being open enough at points to show how large the space is. At times you are in tightly confined tunnels and at other times you are on ledges overlooking a vast expanse below. If anything the open space almost seems too big to be found in the space where it is located, but hey, it’s a game and it’s pretty, so we’ll let it slide.

A map of the Stonecore

The trash creatures (enemies in an instance that are not the boss) are varied and challenging, especially the first few groups. When you first enter the instance you will find Millhouse Manastorm, whom you should recognize from the past, helping out the first few groups against you.  These groups are a pretty tough check to see if you are ready for the instance.  They all do significant damage and need to be controlled until each one goes down.  In addition to the creatures you also need to deal with Millhouse, dropping his health low enough that he retreats to the next group of creatures. If you can get by the first few groups you should be ok until you get to the final boss, as these groups are almost more difficult than the first few bosses


Corborus is the first boss in the instance and appears as a giant elemental worm made up of rock rings as segments. He is a very cool looking boss especially since he matches the theme so well.

Corborus Abilities


Burrow – Corborus tunnels under the ground, releasing weak adds above him.  Also deals significant damage (20,000+) to anyone that does not move away from him.
Crystal Barrage– Sprays small crystal shards at a target and leaves them on the ground for a short while.  They deal damage over time to anyone that remains withing 5 yards of them.
Dampening Wave –This is a frontal cone attack that deals shadow damage and applies a debuff that absorbs 400 points of healing. The debuff stacks up to 20 stacks. Make sure Corborus is faced away from the group.

Corborus Strategy

The fight is not that difficult, as it is made up of two simple phases. In the first phase Corborus will be above the ground.  The tank simple needs to keep him faced away from the group. Anyone targeted by the Crystal Shards simply waits until the shards start flying at them and then moves out of them.  Anyone else in the area needs to move away as well.

After a certain amount of time Corborus will dig into the earth.  At this point you can only see where he is by watching the heaving ground.  It is imperative that everyone watch where he is and move out of his way.  Anyone caught above him will take significant damage and be thrown through the air and potentially too far from the group to be healed.  During this phase he will also spawn small adds continuously.  They are very weak and plays simply need to kill them before there are to many up at once.

After a while Corborus will get bored playing in the mud and surface to deal with you once again.  This returns the fight to phase one.  Defeat him and move on.

Corborus Heroic Mode

There are a few differences with the Corborus fight that make a big difference when done in Heroic mode. This is of course in addition to the much higher health and more base damage caused by all heroic bosses.

The first real difference is that the Crystal Barrage does significantly more damage and has a secondary effect. Once landed the crystals will float up and towards a random player, if they hit that player they explode for upwards of 40,000 damage. They need to be AOE'ed down as quickly as possible.

Secondly, when Corborus is burrowed underground he does more damage to the group and can leap in the air. If he lands on you the damage caused will kill you, so keep moving. To allow a little more time for players to avoid Corborus's burrow phase, the tank should hold him significantly farther away from the group than in normal mode.

Lastly, the adds that surface while Corborus is underground have much more health, cause more damage, and apply a bleed debuff. Killing them fast is critical, they are not a joke like they are in normal mode.


Slabhide is an undead looking dragon that you must defeat.  Expect the normal dragon abilities, meaning stay away from his front arc and away from his tail.  He of course has other abilities as well, but whenever you’re fighting a dragon it’s a good idea to keep those basics in mind.

Slabhide Abilities


Ceiling Collapse – While Slabhide is in the air he can knock down stalactites from the ceiling.  A shadow will appear to show where the stalactite is going to drop.  If you are there when hit hits the ground you will take a lot of damage.
Sand Breath –
This breath attack hits everyone in Slabhide’s front arc and within 20 yards for significant damage.
Eruption– Slabhide targets an area that explodes causing fire damage to anyone on the marked spot. Also a pool of lava will be left behing that lasts for roughly 10 seconds causeing fire damage to anyone silly enough to stand in it.

Slabhide Strategy

The fight is fairly simple fight that is split into two phases.  In the first phase when you first engage Slabhide the tank simply needs to face him away from the rest of the party and hold him there.  The group needs to DPS Slabhide while avoiding any magma bursts that are thrown their way.

After a period of time Slabhide will disengage and fly into the air.  While in the air he will tear stalactites off of the ceiling to fall down onto players.  There will be a shadow that shows up to show where it will land.  Simply move out of the shadow to avoid the damage.  You have roughly 3 seconds which is a lot of time to avoid the damage.

Once he lands the tank simply picks him back up and faces him away again.  This restarts the first phase.  Repeat as required until you have defeated him. Keep in mind though that there can be a large number of stalactites and they do block line of sight, so check your LOS to your healer often.

Slabhide Heroic Mode

Slabhide is a difficult fight for many groups on normal mode due to the LOS issues caused by the stalactites, and it gets even worse in heroic mode. This is due to more damage being caused that needs to be healed and an additional ability that he gains in heroic mode.

The ability is called Crystal Storm and is cast at some point after Stalactites have fallen. The group is given some warning that he is about to cast and then he spays out crystals in all directions and anyone that is in LOS of him is hit for roughly 20,000 damage per second for 6 seconds. The only way to avoid the damage is to find cover behind a stalactite. This however will block all incoming heals as well while you hide.

Once the Crystal Storm is over, the fight reverts back to the ground phase.

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NOTE: This guide has been updated to include all the information on the both the Normal and Heroic versions on the bosses.


The third boss in the instance is the giant Ozruk.

Ozruk Abilities


Elementium Armor – This buff fuses the plates of armor on Ozruk granting him a 20% chance to reflect spells for 10 seconds.
Enrage – When you lower Ozruk to 20% health he enrages, this increases his attack speed and damage output.
Ground Slam – This is a channelled ability, so you have 3 seconds of warning time to clear out. When it goes off anyone within roughly 10 yards is hit for almost 100,000 physical damage.
Spike Shield – This buff lasts for 10 seconds on Ozruk.  While active spikes coat his body and anyone hitting him with melee attacks suffers a stacking bleed effect.  The bleed does roughly 500 damage each second for 3 seconds and stacks up to 20 times.
Spike Barrage – When Ozruk’s spike shield fades the spikes are launched outwards, dealing damage to anyone within about 10 yards and pushing them back.

Ozruk Strategy

This fight revolves around avoiding the knockbacks caused by spike barrage and avoiding the ground slams.  The tank should pull him towards one of the walls in the corridor behind where he spawns and face him towards it.  This way the tank can not be thrown backwards.

Everyone else lines up behind Ozruk so they are only thrown into the opposite wall and not into a group of adds in the room (assuming you did not clear all the adds).

When the spike shield comes up melee DPS should back away and stop DPSing so they do not over tax the healer and are out of range for the barrage that follows.  If you are melee DPS and attack slowly (ie: not rogues or feral druids) then you can attack a little before backing out. Once the spikes fade everyone can move back in. When you see Ozruk wind up for a ground slam everyone including the tank should run away from him and setup on the opposite wall.  The fight continues once he has finished casting.

Be ready for more damage once he enrages, but other than that the fight is the same.  Avoid the big hits and move on to the final boss.

Ozruk Heroic Mode

This boss becomes significantly more difficult on heroic. He gains two abilities that can cause wipes to occur. Also two of his abilities have the very likely possibility of killing the tank outright if not avoided correctly.

The two new abilities for heroic are Paralyze and Shatter. Paralyze lasts 6 seconds or until you take damage and hits everyone. Shatter is cast right after paralyze and takes 2.5 seconds to cast. Once done Ozruk deals roughly 150,000 damage to anyone within 15 yards. Ouch! Also the ground slam ability that he had in normal mode hits much harder, up to 100,000 damage. This means that the tank needs to avoid both of those abilities at all costs.

To do this the tank must make sure they have the bleed debuff caused by hitting Ozruks shield at all times, so that they will take damage once paralyzed and be able to get away. The tank must move as soon as they see paralyze start to be cast. Any delay or misjudge in direction will mean they will not get far enough in time. Also if you have any amount of server latency over about 200ms, don't even bother, you will not be able to react fast enough.

In addition due to all the AOE damage caused everyone else should stand far away from the boss and away from where the tank will be moving to. A good organization is to completely clear the room just before and setup DPS and healer on one side of the tunnel entrance and when the tank runs, he runs to the other side. This way if the tank ends up with Ozruk a little closer after a run back the group should still be far enough away to not get hit.

This is an extremely hard fight, and is almost entirely up to the tank for timing the runs. Expect some wipes as the tank learns this fight.

High Priestess Azil

The last boss in the Stonecore is the High Priestess Azil. When you reach her you get to have some fun clearing several big AoE groups. Once the AoE groups are down though, you need to worry about her.

High Priestess Azil Abilities

High Priestess Azil

Gravity Well – This is a void zone created on the ground below a player, any player or add in that area will suffer damage.
Energy Shield – When up all damage taken is reduced by 75%.
Force Grip – This channelled ability targets the tankand slams him up and down in the air dealing damage and him thrown away from Azil.  This spell can be interrupted, and should be as often as possible.
Throw Rocks – Using the same ability as force grip but instead targeting a nearby rock or boulder. Azil throws the rock at the ground near a player. A shadow will appear where it is going to land, if you are too close when it does you will suffer physical damage.

High Priestess Azil Strategy

This is a two phase fight, however some abilities are used in both phases. Throughout the fight Azil will summon groups of adds. These come in packs and while individually they do not have much health or deal much damage, they must be dealt with before too many are up at once. Also throughout the fight she will summon gravity wellaround the room. Because these portals damage everything (players and adds) they can be used to help control the adds that enter the fight. The group should try to always position them selves on the opposite side of a gravity well so that all adds need to come through it to get to them, in this way most of the adds will die without needing to be touched by players.

In the first phase Azil will jump off of her ledge and join the fight physically. While on the ground she will cast force grip repeatedly, usually on the tank but can be on any player. This makes aggro difficult for the tank if it is not interrupted constantly. After a while Azil will jump back onto her platform, this starts phase two.

During phase two Azil will cast energy shield on herself, stopping much of the damage you can cause to her. She also starts hurling boulders around the room in an attempt to squish players. The shadows appear fairly early to show where they are going to land though so are easy to avoid. Avoid the boulders, portals, and deal with the adds until she gets bored and rejoins the fight.

The phases alternate until you have defeated Azil.

High Priestess Azil Heroic Mode

This boss stays very much the same as in normal mode, with only one new ability added. That ability is called curse of blood and ups all physical damage taken. It is cast on a random target and needs to be removed very quickly, as anyone, the tank included, will not be able to take many hits with it up.

Other than that the fight remains the same as normal only with more damage and more adds. It becomes critical that players interrupt the force grip ability so that the tank can actually pick up adds. It is also critical that players avoid gravity well damage and the boulders being thrown around as both can kill players if you not careful.

Additional Notes on The Stonecore

The instance is a lot of fun and flows very well. There are several different sub areas and each has a distinctive feel, yet they still feel cohesive with the rest of the instance. The scenery while dark overall, after all you’re in a cave, is very nice and has some bright spots and some scenic views off some of the ledges. It’s also neat to see Millhouse Manastorm in an instance again, even though he is not helping you this time.

Some great scenary awaits in the Stonecore

The fights in this instance are all fun and challenging, even though it feels like some of the early trash is harder than the early bosses. The fights in the instance as a whole are more difficult than many past instances, but this is Cataclysm and you're over level 80, so that should be expected. It seems like Blizzard has realized that at this point players have had to make it past 80 levels and some skill should be expected.  Hurray!

A prime example of this is some of the big huge hits that bosses can put out. There are several attacks that can instant kill even the tank if you are not paying attention. Any DPS hit by the bosses is pretty much gone instantly. This is how it should be, you should be made to pay if you are not focused.

Gear wise and progression wise, this instance fits in as you level from 82-83. Even if you were a raid geared level 80, you will find gear upgrades here.

This is yet another instance that really shows that Blizzard took their time with Cataclysm for good reason. They took what was good about past instances and further refined it here. The instance is challenging, yet fun, and can be completed in less than 40 minutes. Great work Blizzard, keep it up!

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Last Updated: Mar 29, 2016

About The Author

Byron has been playing and writing about World of Warcraft for the past ten years. He also plays pretty much ever other Blizzard game, currently focusing on Heroes of the Storm and Hearthstone, while still finding time to jump into Diablo III with his son.